Skip to main content
. 2017 Oct 17;7:13324. doi: 10.1038/s41598-017-13187-5

Figure 7.

Figure 7

IR absorbance spectra of Tasbacka soft tissues and Sepia eumelanin. The Tasbacka spectrum exhibits broad-band absorbance in the 900–1,750 and 2,700–3,700 cm−1 regions, consistent with the natural eumelanin standard. Differences (marked with ‘+’) can be attributed to contributions from the sedimentary matrix (mainly calcite)20,68. These occur also in previously analysed samples from the Fur Formation20. For example, the intense and broad peak at ~1,450 cm−1 likely includes absorbance from the asymmetric stretch mode of calcium carbonate68.